AP Biology--gas exchange in animals

Which of the following is not one of the principal types of surfaces used by animals for direct gas exchange?
a. bronchial tubes
b. body surface
c. gills
d. alveoli
e. all of the above are surfaces for gas exchange

a. bronchial tubes

These are large diameter tubes leading to the lungs, and perhaps supported by rings of stiff material. They're not the small tubes or sacs you'd expect for a gas exchange surface.

i would say a, bronchial tubes...aren't these composed of some amount of cartilage? there's no way gas exchange can occur across that! I do know that b,c, and d are correct for sure though

Bronchial tubes, or bronchi, are not used directly for gas exchange.

body surface, if it means the skin? if it means the nose then i am wrong